12 research outputs found
INVESTIGATIVE STUDY OF THERMAL PERFORMANCE OF THERMOSYPHON SOLAR COLLECTOR
No full textExperimental and Numerical investigation has been performed to improve the thermosyphon thermal performance. Optimization process concentrated on both the water and the operating liquid temperature inside the tank and the thermosyphon. For this purpose, three different models of improvement methods have been studied that depend on increasing the surface area with no changing in the volume of operating liquid. The first one (case-A-) is by add ten ring fins about the absorber pipe. The second method (Case-B-) is by add twenty ring fins about the absorber pipe. While, the third way (Case-C-) is by add ten ring fins with ten grooves about the absorber pipe. The thermosyphon thermal performance was compared between the traditional model and experimental model. Moreover, numerical simulate for all cases were done with computational fluid dynamic (CFD), ANSYS 19.R3. It was observed through the results that a good convergence between the numerical and, experimental results. Furthermore, the thermal performance for case-A- is found greater than all other cases under study
Structural properties of charged compact stars with color-flavor-locked quarks matter
No full textA. Pradhan thanks IUCCA, Pune, India for providing facilities under associateship programmes. Author G.P. thanks the Fundacao para a Ciencia e Tecnologia (FCT), Portugal, for the financial support to the Center for Astrophysics and Gravitation CENTRA, Instituto Superior Tecnico, Universidade de Lisboa, through the Project Nos. UIDB/00099/2020 and PTDC/FIS-AST/28920/2017
The study of behavior titanium pure commercially coated with hydroxyapatite and zirconia
No full textA numerical study of the effect of graphene nanoparticle size on brownian displacement, thermophoresis, and thermal performance of graphene/water nanofluid by molecular dynamics simulation
No full textBrownian motion, often known as BM, is an inherent characteristic of minute particles suspended in a fluid. It plays an important role in several physical and chemical processes. Thermophoresis refers to the process where particles in a fluid are carried along with a gradient in temperature (Temp). This feature has significant importance in several applications, including microfluidics, thermal control, and energy conversion. Through the examination of the thermophoresis phenomenon in water/graphene nanofluid (NF), researchers might get valuable knowledge on the potential uses of these materials. The current study examined the effect of various sizes of graphene nanoparticles (NPs) (5, 6, 9, and 10 Å) on the thermal behavior (TB), BM, and thermophoresis of water/graphene NF using molecular dynamics (MD) simulation. This study reported the changes in heat flux (HF), thermal conductivity (TC), average Brownian displacement (BD), and thermophoresis. It is concluded that by increasing the size of graphene NPs from 5 to 10 Å, the average BD and thermophoresis increased from 3.06 Å and 23.88 Å to 4.16 Å and 31.46 Å, respectively. Due to their higher kinetic energy (KE) and momentum, larger graphene NPs experienced more BM, enabling them to withstand random thermal fluctuations more effectively than smaller particles. In addition, as the size of graphene NPs increased, the HF and TC values increased from 39.54 W/m2 and 0.36 W/(m.K) to 47.19 W/m2 and 0.51 W/(m.K) after 10 ns. Therefore, the size-dependent changes in BD and thermophoretic effects led to a simultaneous increase in HF and TC of the NF, which was attributed to the larger heat transfer (HT) surface area, improved HT properties, and synergistic effects of larger graphene NPs. The maximum (Max) temperature increases from 1415 K to 1504 K. These findings were useful in a variety of industries, particularly for improving TB in different NFs. © 2024 The Author(s
Foliar nano-fertilization enhances fruit growth, maturity and biochemical responses of date palm
No full textThe experiment was conducted in the Abi Al-Khaseeb orchard, Basrah, Iraq during the 2019 season, on date palm (Hillawi cv.). The effect of foliar nano-fertilizer on the response of the growth and fruit ripening rate was amid. Adding nano-fertilizer to the annual date palm fertilization program improved growth and increased production. A comparison of foliar NPK (1, 2 g L-1) as nano-fertilizer and traditional fertilizer, and combined, was applied. The results revealed that the treatment of foliar traditional and nano-fertilizers together increased the weight of fruit and bunches, water content, indoleacetic acid, and gibberellic acid relative to other treatments. Nano-fertilizers (1g L -1) led to an increase in fruit ripening rate, dry mass, and total soluble solids, activity of the enzymes peroxidase, and superoxide dismutase, and abscisic acid content. The leaflet protein expression shows that the appearance of protein bands 1 to 5 and 6 was up-regulated by control and traditional fertilizer. Whereas the protein bands 6 and 7 were down-controlled under nano-fertilizer. Hierarchical cluster analysis of proteins in the leaf in response to traditional and nano-fertilizer showed two distinct clusters. The use of nano-fertilizer individually leads to the acceleration of fruit ripening. while the production fruit that is increased using foliar nano-fertilizer with traditional fertilizer.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Mitogenomes from Two Uncommon Haplogroups Mark Late Glacial/Postglacial Expansions from the Near East and Neolithic Dispersals within Europe
No full textThe current human mitochondrial (mtDNA) phylogeny does not equally represent all human populations but is biased in favour of representatives originally from north and central Europe. This especially affects the phylogeny of some uncommon West Eurasian haplogroups, including I and W, whose southern European and Near Eastern components are very poorly represented, suggesting that extensive hidden phylogenetic substructure remains to be uncovered. This study expanded and re-analysed the available datasets of I and W complete mtDNA genomes, reaching a comprehensive 419 mitogenomes, and searched for precise correlations between the ages and geographical distributions of their numerous newly identified subclades with events of human dispersal which contributed to the genetic formation of modern Europeans. Our results showed that haplogroups I (within N1a1b) and W originated in the Near East during the Last Glacial Maximum or pre-warming period (the period of gradual warming between the end of the LGM, ~19 ky ago, and the beginning of the first main warming phase, ~15 ky ago) and, like the much more common haplogroups J and T, may have been involved in Late Glacial expansions starting from the Near East. Thus our data contribute to a better definition of the Late and postglacial re-peopling of Europe, providing further evidence for the scenario that major population expansions started after the Last Glacial Maximum but before Neolithic times, but also evidencing traces of diffusion events in several I and W subclades dating to the European Neolithic and restricted to Europe
Citizenship and political participation in the State of Kuwait : the case of National Assembly (1963-1996)
No full textEThOS - Electronic Theses Online ServiceGBUnited Kingdo
Infection and mortality of healthcare workers worldwide from COVID-19 : A systematic review
No full textObjectives To estimate COVID-19 infections and deaths in healthcare workers (HCWs) from a global perspective during the early phases of the pandemic. Design Systematic review. Methods Two parallel searches of academic bibliographic databases and grey literature were undertaken until 8 May 2020. Governments were also contacted for further information where possible. There were no restrictions on language, information sources used, publication status and types of sources of evidence. The AACODS checklist or the National Institutes of Health study quality assessment tools were used to appraise each source of evidence. Outcome measures Publication characteristics, country-specific data points, COVID-19-specific data, demographics of affected HCWs and public health measures employed. Results A total of 152 888 infections and 1413 deaths were reported. Infections were mainly in women (71.6%, n=14 058) and nurses (38.6%, n=10 706), but deaths were mainly in men (70.8%, n=550) and doctors (51.4%, n=525). Limited data suggested that general practitioners and mental health nurses were the highest risk specialities for deaths. There were 37.2 deaths reported per 100 infections for HCWs aged over 70 years. Europe had the highest absolute numbers of reported infections (119 628) and deaths (712), but the Eastern Mediterranean region had the highest number of reported deaths per 100 infections (5.7). Conclusions COVID-19 infections and deaths among HCWs follow that of the general population around the world. The reasons for gender and specialty differences require further exploration, as do the low rates reported in Africa and India. Although physicians working in certain specialities may be considered high risk due to exposure to oronasal secretions, the risk to other specialities must not be underestimated. Elderly HCWs may require assigning to less risky settings such as telemedicine or administrative positions. Our pragmatic approach provides general trends, and highlights the need for universal guidelines for testing and reporting of infections in HCWs. © Author(s) (or their employer(s)) 2020
